Guidewire with adjustable stiffness

ABSTRACT

A medical guidewire system including an inner member having an outer diameter and an outer member having an inner diameter, the inner diameter being larger than the outer diameter. The inner and outer members are relatively slidable to adjust a stiffness of the guidewire system. The lumen of the outer member forms a gap for fluid flow therethrough. A connector to the inner member and a fluid infusion channel communicating with the gap for injection of fluid through the gap to exit a distal portion of the outer member.

BACKGROUND OF THE INVENTION

This application is a continuation of pending patent application Ser.No. 12/660,891 filed Mar. 5, 2010 which claims priority from provisionalpatent application 61/159,178, filed Mar. 11, 2009 and from provisionalpatent application 61/257,483, filed Nov. 3, 2009, and is a continuationin part of patent application Ser. No. 12/082,507, filed Apr. 11, 2008,now abandoned, (which claims priority from provisional application Ser.No. 60/913,489, filed Apr. 23, 2007 and provisional application Ser. No.61/008,100, filed Dec. 17, 2007. The entire contents of each of theseapplications are incorporated herein by reference.

TECHNICAL FIELD

This application relates to a medical guidewire and more particularly toa medical guidewire system with adjustable size and stiffness.

BACKGROUND OF RELATED ART

Guidewires are currently being used in medical procedures to guidecatheters, sheaths or other devices from a remote site to a surgicalsite. From a remote part of the body, a guidewire is introduced into anartery or vein. The guidewire is then advanced through the vascularsystem to the target site where an angiogram, balloon, stent, catheteror other vascular device is to be positioned. The guidewire thenfunctions as a rail for advancement of these devices.

Currently, a soft small diameter wire, such as a 0.014 wire, is utilizedinitially to advance in the artery or vein. During advancement,especially through tortuous anatomy, the soft wire may lack therequisite pushability to advance around a curve. Also, due to itssoftness/flexibility, it may be difficult to advance a catheter over itto perform the surgical, e.g. diagnostic and/or interventional,procedure. In these instances, this flexible wire needs to be exchangedfor a stiffer and/or larger wire. To exchange the guidewire, severalsteps are required. First, an exchange catheter is advanced over thesoft wire. Second, the soft wire is removed. Third, the stiffer wire isinserted through the exchange catheter. Fourth, the exchange catheter isremoved, leaving the stiffer wire in place. Such wire exchanges are timeconsuming and require two separate wires and an exchange catheter.Furthermore, these steps also increase risks to the patient such asincreased risk of infection and increased chance of damaging the vesseldue to the added insertion and removal of the wires through the vascularsystem as well as possible loss of wire position and critical time loss.

Even after exchange for the larger wire, sometimes the requisitestiffness and pushability to advance through a curved vessel portion isstill lacking and therefore the wire needs to be exchanged for yet aneven stiffer wire. This requires an additional wire exchange utilizingthe time consuming four step method described above.

After such exchange for a stiffer wire and advancement around thetortuous portion of the anatomy, a stenosis or restricted passage of thevessel might be encountered through which the larger wire cannot pass.Thus, yet another catheter exchange could be required, this timeexchanging the larger diameter stiffer wire for the smaller diametersofter wire. As a result, multiple guidewire exchanges requiringmultiple insertions of the exchange catheter, multiple removals of thealready inserted wire, and multiple insertions of a new wire from theremote site may be necessary in a single surgical (diagnostic and/orinterventional) procedure. As noted above, this adds undesired time tothe surgical procedure, as well as increases the risk of trauma ordamage to the vessel and loss of desired wire position.

In addition, the inventor has found that in some instances where acatheter exchange is required, the surgical procedure cannot even beperformed. That is, in some instances, the exchange catheter, which hasa larger diameter (typically about 0.040 inches inside diameter) thanthe stiffer replacement wire because it has a lumen to receive the wire,cannot cross the stenosis. In this case, the guidewire with increasedpushability cannot be inserted and advanced to reach the target site,thus not enabling a stent, dilation balloon or other vascular treatmentdevice to be advanced to the surgical site. Consequently, theintralumenal surgical procedure cannot be performed.

As can be appreciated from the above, in the current procedure, multipleguidewires may be required to achieve desired parameters such assoftness to reduce trauma to the vessel during insertion, reduceddiameter to enable access through restricted passages in the vessels andfacilitate access to the surgical site, stiffness/rigidity to allowpushability and stiffness/rigidity to facilitate passage of a catheterthereover. For example, a gentler more flexible guidewire, such as a0.014 inch diameter wire, has the small diameter and softness advantage,but lacks the pushability to advance through some tortuous anatomy. Thelarger diameter guidewire, such as the 0.035 or 0.038 inch diameterguidewire, is more rigid and has better pushability but may be too largefor restricted passages. It may also still lack the necessary stiffness,thus requiring an exchange for an extra stiff wire. The extra stiff wirelacks the flexibility and softness. Thus, the user needs to exchange thewires to obtain the requisite pushability, flexibility and stiffness foraccessing the diagnostic and/or interventional site.

Also, exchange sheaths, when used with a 0.014 guidewire, present arelatively large stepped transition from their distal end to the smallerdiameter 0.014 guidewire, therefore creating a more traumatic “snowplow” effect during insertion.

Therefore, it would be advantageous to provide a guidewire system whichprovides the desired diameter, pushability, flexibility and stiffnesswithout requiring guidewire exchanges and exchange catheters, therebyeliminating the foregoing disadvantages of such exchanges.

It would also be advantageous if fluid, such as contrast, could beinjected through the guidewire system for visualization.

SUMMARY OF THE INVENTION

The present invention overcomes the problems and deficiencies of theprior art. The present invention provides in one aspect a medicalguidewire system comprising a first inner member having a first outerdiameter, a second intermediate member having a second outer diameterlarger than the first outer diameter, and a third outer member having athird diameter larger than the second outer diameter. The second memberhas a longitudinally extending opening to receive the first member forrelative sliding movement with respect to the first member and the thirdouter member has a longitudinally extending opening to receive thesecond member for relative sliding movement with respect to the firstand second member. The second and third members have an interlockingfrictional engagement and the first and second members have a clampingengagement.

In one embodiment, the third member has a third stiffness greater thanthe first stiffness of the first member, and the second member ismovable with respect to the third member to provide the third memberwith a second stiffness greater than the third stiffness.

In one embodiment, the first member comprises a solid core material. Thefirst and second members in one embodiment are composed at least in partof shape memory metal. In one embodiment, the second and/or thirdmembers comprise hypotubes which can have slots in a sidewall toincrease flexibility.

In one embodiment, the first member includes a slotted member slidablethereon for selected engagement with the second member at a selectedposition.

The present invention in another aspect provides a medical guidewiresystem comprising an inner member having an outer diameter and an outermember having an inner diameter, the inner diameter being larger thanthe outer diameter. The outer member has a longitudinally extendinglumen to receive the inner member. The inner and outer members arerelatively slidable to adjust a stiffness of the guidewire system. Thelumen of the outer member forms a gap for fluid flow therethrough. Aconnector has a first end portion connected to the outer member, asecond end portion connected to the inner member and a fluid infusionchannel communicating with the gap for injection of fluid through thegap to exit a distal portion of the outer member.

The inner member can be selectively lockable with the outer member. Thegap in one embodiment is defined by an annular space between an outerwall of the inner member and an inner wall of the outer member.

In one embodiment, the connector includes a first clamping member at thefirst end portion and a second clamping member at the second endportion. A rotatable knob can be provided at each end portion to providea clamping force on the inner member and on the outer member. Theconnector can include a side arm for delivering fluid to the lumen ofthe outer member.

In one embodiment, the outer member comprises a hypotube having aplurality of slots formed therein.

In another aspect, the present invention provides a medical guidewiresystem comprising an inner member having an outer diameter, an outermember having an inner diameter forming a first lumen, and anintermediate member having a second lumen. The inner diameter is largerthan the outer diameter. The outer member has a longitudinally extendinglumen to receive the intermediate member and the intermediate and outermembers are relatively slidable to adjust a stiffness of the guidewiresystem. The lumen of the intermediate member forms a gap for fluid flowtherethrough, and a connector has a first end portion connected to theintermediate member, a second end portion connected to the inner memberand a fluid infusion channel communicating with the gap for injection offluid through the gap to exit a distal portion of the guidewire system.The connector includes a first clamping member engageable with theintermediate member and a second clamping member engageable with theinner member.

In one embodiment, the inner wire has a locking member thereon movableby engagement with the intermediate member to a locking position to fixthe position of the inner and intermediate members, and the intermediatemember has a flared handle portion frictionally engageable with theouter member to fix the position of the outer and intermediate members.

DETAILED DESCRIPTION OF THE DRAWINGS

Preferred embodiment(s) of the present disclosure are described hereinwith reference to the drawings wherein:

FIG. 1 is a perspective view of the guidewire system of the presentinvention showing the intermediate (stiffener) wire and outer wire inthe retracted position to expose the inner wire;

FIG. 1A is an exploded perspective view of the guidewire of FIG. 1;

FIG. 1B is a longitudinal cross-sectional view of the guidewire of FIG.1 showing the outer wire and the intermediate stiffener wire in theadvanced position;

FIG. 2 is a perspective view of an alternate embodiment of the guidewiresystem of the present invention showing the intermediate (stiffener)wire and outer wire in the retracted position to expose the inner wire;

FIG. 2A is a longitudinal cross-sectional view of the guidewire of FIG.2 showing the outer wire and the intermediate stiffener wire in theadvanced position;

FIG. 3 is an anatomical view illustrating the guidewire of the presentinvention being inserted through the femoral artery for subsequentadvancement through the vascular system, e.g. to the external carotidartery (the shuttle sheath not shown for clarity);

FIG. 4 is a longitudinal cross-sectional view of the guidewire of FIG. 1showing the outer wire and the intermediate stiffener wire in theretracted position to expose the inner wire, corresponding to theposition of the wires in FIG. 1;

FIG. 5 is a longitudinal cross-sectional view of the guidewire of FIG. 1showing the outer wire in the advanced position and the intermediatestiffener wire in the retracted position;

FIG. 6 is a perspective view of an alternate embodiment of the guidewireof the present invention having a modified distal tip, and illustratingthe outer wire and intermediate stiffener wire in the retracted positionto expose the inner wire;

FIG. 7 is a longitudinal cross-sectional view of the guidewire of FIG. 6except showing the outer wire in the advanced position and theintermediate wire in the retracted position;

FIG. 8 is a perspective view of a proximal end of the guidewire of thepresent invention showing attachment of a conventional extension wire tothe inner wire;

FIG. 9 is an enlarged cross-sectional view taken along line 9-9 of FIG.8 showing the attachment of the extension wire to the inner wire;

FIG. 10 is a perspective view of another alternate embodiment of theguidewire system of the present invention, the outer wire shown in theadvanced position and the intermediate stiffener wire in the retractedposition;

FIG. 11 is a longitudinal cross-sectional view of the guidewire of FIG.10 showing the outer wire in the advanced position and the intermediatestiffener wire in the retracted position;

FIG. 12 is a cross-sectional view of an alternate embodiment of thehandle of the inner wire having a threaded engagement for removal fromthe inner wire;

FIG. 13 is a perspective view of an alternate embodiment of theguidewire system of the present invention showing the intermediate(stiffener) tube and outer tube in the retracted position to expose theinner wire;

FIG. 13A is a cross-sectional view taken along line A-A of FIG. 13showing the distal region of the outer tube (the inner wire removed forclarity);

FIG. 13B is an exploded perspective view of the guidewire of FIG. 13;

FIG. 14 is an enlarged view of the guidewire of FIG. 13 showing thehandles in the retracted unlocked position;

FIG. 15 is a perspective view of the inner wire handle of FIG. 14engaged (interlocked) with the stiffener handle prior to locking;

FIG. 16 is a perspective view similar to FIG. 15 showing the inner wirehandle rotated to lock the inner wire and stiffener;

FIG. 17 is an enlarged view of the stiffener tube of FIG. 13;

FIG. 18 is an enlarged view of an alternate embodiment of the stiffenertube;

FIG. 18A is an enlarged view of an alternate embodiment of the outertube;

FIG. 18B is an enlarged view of an alternate embodiment of the outertube;

FIG. 19 is an enlarged perspective view of a proximal portion of analternate embodiment of the guidewire system of the present inventionshowing the inner wire and stiffener tube in the retracted position;

FIG. 20 is a perspective view showing the handles of FIG. 19 prior toengagement;

FIG. 21 is a cross-sectional view of the handle of the inner wire ofFIG. 19 prior to attachment to the inner wire;

FIG. 22 is an enlarged perspective view of a proximal portion of anotheralternate embodiment of the guidewire system of the present inventionshowing the inner wire and stiffener in the retracted position;

FIG. 22A is an enlarged view of the locking member of the inner wire ofFIG. 22;

FIG. 23 is a cross-sectional view illustrating the threaded lockingmember of the inner wire spaced from the threaded portion of thestiffener collar;

FIG. 24 is a cross-sectional view of the threaded locking membersengaged for rotation to fix the inner wire axially with respect to thestiffener tube; and

FIG. 25 is a perspective view of a proximal portion of another alternateembodiment of the guidewire system of the present invention showing theinner wire in the retracted position;

FIG. 26 is a perspective view of another alternate embodiment of theguidewire system of the present invention;

FIG. 27 is a close up perspective view of the threaded interlock of theintermediate and outer members of FIG. 26;

FIG. 28 is a close up perspective view of the clamping interlock of theintermediate and inner members of FIG. 26;

FIG. 29 is a cross-sectional view of an alternate embodiment of theguidewire system of the present invention having a connector for fluidinjection;

FIG. 29A is a perspective view of the inner wire, intermediate and outertube of FIG. 29;

FIG. 30 is a cross-sectional view of another alternate embodiment of theguidewire system of the present invention having a connector for fluidinjection;

FIG. 31 is a cross sectional view of the distal portion of the guidewiresystem of FIG. 30 showing the inner member in an advanced position.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Turning now to the drawings, wherein like reference numerals identifysimilar or like components throughout the several views, the guidewiresystem of the present invention is illustrated. The guidewire systemcomprises a guidewire 10 have three coaxial members, or in someembodiments two coaxial members, movable with respect to one another toadjust the stiffness and size (outer diameter) of the guidewire.

More specifically, the guidewire system 10 in the embodiment shown inFIGS. 1-5, comprises a small diameter inner member 20, an intermediatestiffener member 30 slidable over the inner member 20, and a largerdiameter outer member 40 slidable over the intermediate member 30 andthe inner member 20. As used herein, the term “proximal” refers to thepart or component of the system closer to the user and the term “distal”refers to the part or component further from the user. The term memberas used herein includes a wire, tube or other structure of the inner,intermediate and outer components of the guidewire system.

The small diameter inner member 20, in a first embodiment, is a wirehaving a spherical or ball tip 22 either integral or attached thereto.The ball tip 22 provides a blunt atraumatic leading end of the wire toreduce trauma to the vessel during advancement. The ball tip 22 is alsopreferably dimensioned so it has a larger diameter (transversedimension) than the diameter of the lumen 42 of the outer wire 40 or atleast larger than the diameter of the opening to the lumen 42. Thus, italso acts as a stop to prevent withdrawal of the entire wire 20 throughthe outer wire 40 and acts as a stop to limit distal movement of theouter wire 40 so it does not extend over the tip 24 so that a blunt tipcan remain as the leading edge for the guidewire 10 to provide asmoother passage. This is shown for example in FIG. 2 where the surface22 a of the tip 22 would abut the distalmost end 40 a of outer wire 40.

It should be appreciated that tips other than ball tips can be utilized.For example, FIGS. 6 and 7 show a conical tip 22′ of inner wire 20′having a smother transition and functioning similar to ball tip 22. Inall other respects, guidewire 10′ of FIG. 6 is identical to theguidewire 10 of FIG. 1. The guidewire 10′ is shown in FIG. 6 with theintermediate wire 30′ and outer wire 40′ retracted to expose the innerwire 22′ and shown in FIG. 7 with the outer wire 40′ advanced to itsdistal position.

Additionally, it should be appreciated that an enlarged tip need not beprovided. For example, in the alternate embodiment of FIG. 2, the distaltip of the inner wire is the same diameter as the portion proximal ofthe distal tip.

The inner wire forms the core wire of the system, and is preferablyformed of a solid core and can be composed at least in part of a shapememory material such as Nitinol. Non-metallic materials can also beutilized, such as Pebax. The inner wire in one embodiment can have acoil and core combination towards its distal end and is a solid wiretowards it proximal end. Other materials such as stainless steel arealso contemplated. Preferably the wire 20 has an outer diameter of about0.014 inches, although other dimensions are also contemplated.Preferably, the inner wire 20 has a greater degree of flexibility and issofter than the other two wires 30, 40. In one embodiment, for example,the coil wire is composed of a stainless steel wire with a platinum coilat a distal tip over a reduced diameter of the stainless steel wire, andhas a PTFE coating.

The stiffener member 30 forms the intermediate wire as it is positionedbetween the inner wire 20 and outer wire 40. Stiffener wire 30 can beformed from single or multiple wires wound together, having a lumen 32with a dimension (diameter) larger than the outer diameter of the wire20 so it can slide over wire 20 (or wire 20 can slide within it). In apreferred embodiment, the stiffener wire 30 has an outer diameter ofabout 0.018 inches, although other dimensions are also contemplated. Thewire 20 can be formed of a shape memory material such as Nitinol,although other materials, such as stainless steel, are alsocontemplated. In one embodiment, the stiffener has a stiffness/rigiditygreater than the stiffness of the inner wire 20 and outer wire 40.However, the stiffener can alternatively have a stiffness less than thestiffness of the outer wire/and or inner wire, provided it hassufficient stiffness such that when it is advanced, it stiffens a distalregion of the outer wire (and overall guidewire system) by providing adistal region of increased wall thickness due to the combination ofstiffener and outer member. That is, in such embodiment, advancement ofthe stiffener provides a thicker walled and thereby stiffer/more rigidwire.

The stiffener, in an alternate embodiment, is in the form of a slottedhypotube which is described in more detail below.

The outer wire 40 has a longitudinally extending opening or lumen 42with a dimension (diameter) larger than the outer diameter of theintermediate wire 30 so it can slide over wire 30 and smaller wire 20(or wire 30 can slide within it). In a preferred embodiment, the outerdiameter of the wire is between about 0.035 inches to about 0.038inches, although other dimensions are also contemplated. In oneembodiment (not shown) the outer wire 40 is a wound wire wound in onedirection. It could be a round wire or a rectangular wire.Alternatively, it can comprise a series of wound or twisted wires. Thewire 40 can also have a hydrophilic and/or a PTFE coating. It can alsobe formed with a coated or uncoated plastic jacket. A safety wireconnected to proximal and distal portions of the outer wire couldoptionally be provided. The outer wire 40 has a stiffness/rigiditygreater than the stiffness of the inner wire 20. In some embodiments,the outer wire can also have a stiffness less than thestiffness/rigidity of the intermediate wire 30 as discussed above.

In an alternate embodiment, the outer tube is in the form of a slottedhypotube which is described in more detail below.

In the alternate embodiment of FIGS. 2 and 2A, inner wire 50 does nothave an enlarged tip but terminates in a tip 52 of the same diameter.Outer wire 60 has a thicker wall portion at the distal end portion 62 tocreate a shoulder 62 b and a reduced lumen diameter 62 a. The shoulder62 b can form a stop to limit distal advancement of the stiffener 70such that the distalmost end of the stiffener, although extending to adistal region of the outer wire 60, cannot extend to a distalmost end ofthe outer wire 60. The reduced lumen area 62 a creates a tighter fit forthe inner wire 20 as it slides more closely around the inner wire 50 tolimit entry of material into the lumen of the outer wire 60. The tighterfit also enables clot to be wiped off the inner wire 50 upon movementwith respect to the distal tip 63 of outer wire 60. The tip 63 also hasa smooth shallow taper (similar to the outer wire 40 of FIG. 1) toprovide a smoother transition and facilitate advancement over the innerwire 50 in very tight and tortuous anatomy with reduced trauma. Tipswith even more gradual tapers could be provided. In all other respects,the guidewire system of FIG. 2 is the same as FIG. 1.

In one embodiment, the inner wires described herein have a length ofabout 3.0 m, the intermediate wires or tubes described herein have alength of about 2.36 m to about 2.38 m and the outer wires or tubesdescribed herein have a length of about 2.4 m to about 2.6 m. In anotherembodiment, the intermediate wires or tubes described herein have alength of about 1 m to about 2 m, and preferably about 1.8 m, and theouter wires or tubes described herein have a length of about 1 m toabout 2 m, and preferably about 1.8 m. It should be understood thatthese dimensions are provided by way of example and other dimensions arealso contemplated.

It should be appreciated that sliding movement of the wires (or tubes)referred to herein means that either the outside wire (or tube) ismoving over the held (stationary) inside wire, the inside wire is movingwithin the stationary outside wire, or both wires are sliding inopposite directions. For example, the inner wire can be exposed bymoving the inner wire distally, moving the outer wire (tube) proximally,or moving both wires in their respective directions. However, it may bepreferable that the stiffening wire be advanced or retracted to maintainthe advanced position of the guidewire during insertion. The foregoinglikewise applies to the use of tubes instead of wires as one or more ofthe members of the guidewire system.

The use of the guidewire system will now be described with reference tothe embodiment of FIG. 1, it being understood that such use is alsoapplicable to the other embodiments of the present invention describedherein utilizing the three members in the form of wires or tubes (orother structures).

It is also contemplated that a two component guidewire system beprovided with an inner member and an outer member slidable with respectto one another to adjust the guidewire diameter and to adjust theguidewire stiffness without the use of a stiffener. The inner member andouter member in such system are lockable to one another. Examples ofsuch embodiments are described below.

In use, selective positioning of the three wires with respect to oneanother varies the diameter of the guidewire being advanced through thevascular system and varies the stiffness of the guidewire. Thisindependent sliding movement of the wires provides an in situprogressive transformation of the soft wire, used to avoid damage to thevessel, into a stiff or rigid wire to provide a rail system for easiercatheter advancement thereover and to increase pushability around curvedanatomy.

More specifically, to increase the pushability and stiffness of theguidewire 10, the outer wire 40 is advanced distally over the inner wire20 from the position of FIG. 4 to the position of FIG. 5 (or the innerwire 20 is retracted to the position of FIG. 5). If further stiffness orenhanced pushability is desired, the intermediate wire 30 is advancedfrom the retracted position of FIG. 5 to the advanced position of FIG.1B. Sliding of the wires is controlled by the user at the proximal end.

Note in the embodiment of FIG. 1B, in the advanced position of theintermediate wire 30, it remains spaced proximally from the distalmostend of the outer wire 40 to reduce trauma to the vessel by ensuring someflexibility of the distalmost tip of the guidewire 10. In oneembodiment, in the advanced position, the distalmost end 34 of theintermediate wire 30 is spaced a distance of about 1 centimeter to about4 centimeters, and preferably from about 1 cm to about 2 cm, from thedistalmost end 40 a of outer wire 40. Other spaced distances are alsocontemplated. In the advanced position of the inner wire 20 (FIGS. 1 and4), it can protrude about 30 cm to about 40 cm from the distalmost end40 a of outer wire 40. In other embodiments, it can protrude from about5 cm to about 20 cm from the distalmost end 40 a of outer wire 40. Otherprotruding lengths are also contemplated.

After the guidewire 10 has been stiffened by relative sliding movementof the outer and/or intermediate wire, if a smaller diameter and moreflexible guidewire is desired, the inner wire 20 can again be exposed byretraction of the outer wire 40 (and stiffener wire 30) or advancementof the inner wire 20 (or opposite movement of both).

As can be appreciated, relative movement of the wires can occurrepeatedly as desired to enhance advancement of the guidewire 10 throughthe vascular system to the desired surgical site.

In an alternate embodiment shown in FIGS. 10 and 11, each of the wires120, 130 and 140 of guidewire 100 has a handle portion. Handle portionsas used herein include integral handles, separate handles attached tothe members or a proximal end portion of the member which interlockswith another member. With reference to FIGS. 10 and 11, inner wire 120has a handle 124 at its proximal end, intermediate stiffener wire 130has a handle 134 at its proximal end, and outer wire 140 has a handleportion 144 at its proximal end. This facilitates grasping of the wireby the user as well as facilitates torquing of the wire to rotate thedistal end. One or more of the handles can include a textured surface(see e.g. handle 144 of FIG. 10) to facilitate gripping.

The handles can optionally interlock to fix the positioning of the wireswith respect to one another. FIG. 11 illustrates one way to interlockthe handles. In this embodiment, the engagement regions of the membersinclude an interlocking feature in the form of a taper/recess interlock.More specifically, interlocking is achieved by providing a taper on thedistal portion of handles 124 and 134 which frictionally mate with aproximal recess at the proximal end of the mating handle. Morespecifically, distal tapered region 125 of handle 124 would frictionallyengage with the proximal recess 136 of handle 134 and distal taperedregion 135 of handle 134 would frictionally engage the proximal recess146 of handle 144. Thus, when inner wire 120 is moved relative to theouter wire 140, the user does not need to hold it in this advanced(exposed) position as the handle 124 would interlock with handle 134 tofix the inner wire 120 in position. Similarly, when intermediate wire130 is moved relative to the outer wire 140, the user does not need tohold it in this position as the handle 134 would interlock with handle144 to fix the inner wire 120 and intermediate wire 130 in position.This interlocking of the handles 134 and 144 could also be used tomaintain the spacing between the distalmost ends of the wires 130 and140 as described above with respect to wires 30 and 40. It could also beused to maintain the distal tip of the inner wire 20 as the leading edgeinstead of or in addition to utilizing the larger diameter tip, e.g. theball tip, to achieve this function. The handle for the outer wire isshown as the same dimension of the outer wire so the handle can beconsidered the proximal portion of the wire.

FIGS. 13-17 illustrate an alternate embodiment of the guidewire systemhaving alternate engagement regions providing an alternate mechanism forinterlocking the members. This system has a stiffener and outer memberformed of a tube. The relative stiffness of the inner, intermediate, andouter members can be provided as discussed above.

More specifically, guidewire 210 has an inner member 220, anintermediate stiffening member 230 and an outer member 240. Stiffenermember 230 is in the form of a tube, preferably composed of stainlesssteel, and has a longitudinally extending lumen 232 (FIG. 17)dimensioned to slidingly receive inner wire 220. The stiffener tube 230in the embodiment illustrated in FIG. 17 has a plurality of slots 234formed therein (preferably laser cut into the tube) to increase theflexibility of the tube. Each slot in the illustrated embodiment,extends around a portion of the circumference, for less than 360 degreesand preferably less than 180 degrees. Additionally, the slots arestaggered such that a solid portion of the tube between the spacebetween slots in one row is adjacent a slotted portion of another row.For ease of understanding, three rows of slots have been numbered inFIG. 17 to illustrate how slot portion 236 a of row R2 is adjacent a gap235 b (solid tube portion) between slot portions of row R1 and adjacentgap 237 b (solid tube portion) between slot portions of row R3.

As shown, the axial spacing between the slots in FIG. 17 issubstantially equal. However, it is also contemplated that the spacingbetween the slots can be varied at various portions along the tube toprovide areas of different flexibility. For example, in the embodimentof FIG. 18, the slots of tube 230′ vary such that slots 231 a at thedistal portion of the tube 230′ are closer together (have a shorterdistance d1) than the slots 231 b of a more proximal portion which havea greater distance d2 between them. This provides more flexibilitytoward the distal end. Various slot spacing is contemplated. Forexample, the slots can be varied such that they become progressivelyfurther apart in a proximal direction or discrete regions of the tubecan have slots of substantially equal spacing, but different than otherregions of the tube.

It is also contemplated, that the slots can be formed in a spiralpattern such as shown in FIG. 18A illustrating an outer tube with slots.The outer tube 240′ has spiral or helically arranged slots 249 formed inthe tube, preferably at an angle to the longitudinal axis as shown. Thespiral slots, preferably formed by laser cutting, can be interrupted,leaving a solid wall portion 243 between the sets of spiraling slots.The solid wall portions can be evenly spaced as shown to provide similarsets of slots or can be varied to provide sets having different lengthsof spiraling slots. Such spiraling slots can also be formed on theintermediate stiffener tube. A heat shrink tube (not shown), made of PETfor example, can be positioned over all or a portion of the tube, andpreferably over a distal portion and a hydrophilic coating or jacket canbe provided over the distal portion, preferably for about 30 cm.

In the embodiment of FIG. 18B, gaps 262 b (solid tube portion) of slots260 are radially staggered. The slots 260 are formed in a spiral patternwith the space 263 therebetween (pitch) increased toward a proximal end.Different portions can be of a different constant pitch and/or portionscan be of progressively increasing pitch.

The foregoing slot arrangements can be provided on the stiffener tubeand/or the outer tube. It should be appreciated, however, that inalternate embodiments, the stiffener tube and/or outer tube do not haveslots.

Referring back to FIGS. 13-13C, inner wire preferably is a 0.014″ wireas described above and outer member 240 is in the form of a tube,preferably of stainless steel. The outer tube 240 can have slots in thevarious arrangements as described above with respect to the stiffenertube 230 and the distances between slots can be varied in differentregions of the tube as described above. The outer tube 240 and stiffener230 can have the same or different slot arrangements.

Outer tube 240 has a lumen 242 dimensioned to slidingly receivestiffener tube 230. Outer tube 240 has a distal end portion, best shownin FIG. 13A, having a distal lumen portion 242 a that gradually reducesin diameter, to a diameter E1 at region 242 b, less than the diameter E2at region 242 c. In this manner, diameter E1 can be close to the outerdiameter of the inner wire 230 to reduce any gap between the inner wire220 and outer tube 240 when the inner wire 220 is extended. The innerwall 241 of outer tube 240 is angled to provide a smooth transitionbetween the two diameters E1 and E2 to ease the movement of inner wire220 through lumen 242 to an extended position.

Alternatively, a lead in tube, e.g. tube 850 of FIG. 31, can bepositioned within the outer tube at a distal end having a reduceddiameter portion for the inner member. The lead in tube can be attachedto the outer tube by soldering, e.g. solder 860, or other attachmentmethods. Solder 860 can have a radiused portion to provide a smoothtransition for sliding of the inner wire 820 through outer tube 840. Thelead in tube is shown with the embodiment having a fluid connector(described below), but could also be used in other embodiments describedherein.

In some embodiments, a distal portion of the outer tube can have a PETheat shrink and/or a hydrophilic coating. The PET can have a hydrophiliccoating over a distal portion. Proximal of the distal portion a coatingsuch as PTFE can be provided on the outer tube.

The members in the embodiment of FIGS. 13-16 have engagement regionswith an interlocking feature in the form of a rotational pin and slotarrangement. More specifically, inner wire 220 has a handle 221 with anL-shaped slot 228 at its distal end. Pin 233 at the proximal end ofhandle 231 of stiffener tube 220 engages slot 228. That is, when theinner wire 220 is advanced longitudinally, the pin 233 engages thelongitudinal region 228 a of slot 228 (see FIG. 15). This also acts as astop for longitudinal advancement of the inner wire 220. Once in theslot region 228 a, the inner wire 220 is rotated so that the pin 233enters the transverse slot region 228 b as shown in FIG. 16, therebyfixing the axial position of the inner wire 220 and stiffener 230.Similarly, the intermediate tube 230 has an L-shaped slot 238 at thedistal end of handle 231. A proximal pin 245 of outer tube 240 entersthe longitudinal slot region 238 a and then upon rotation, enters thetransverse region 238 b to fix the stiffener 230 to the outer tube 240.Pin 245 could also be provided on a handle of outer tube 240. Thisinterlocking handle also functions as a stop to limit the extent ofdistal movement of the stiffener tube 230 within outer tube 240.

Note as an alternative to the pin/slot arrangement, two locking tabscould be provided as shown in FIG. 25. Mating tabs 292 and 283 of outertube 290 and of handle 281 of stiffener tube 280, respectively,interlock upon rotation. Similarly, proximal locking tab 282 of handle281 of stiffener tube 280 interlocks with tab 272 of handle 271 of innerwire 270.

FIGS. 19-21 illustrate another embodiment for interlocking the handlesto lock the members to prevent longitudinal movement of the members. Theembodiment is similar to the embodiment of FIG. 11. Inner wire 320 has aproximal handle 321 with a distal tapered region 322. This taperedregion 322 is inserted into the opening 333 of proximal handle 331 ofstiffener tube 330 to frictionally engage the handles. This interferencefit interlocks the handles which thereby interlocks the inner wire 320and stiffener tube 330 to prevent movement of the inner wire 320 withrespect to the stiffener tube 330. The proximal end of outer tube 340has an opening 343 dimensioned to matingly receive the distal taperedregion 332 of handle 331 of intermediate stiffener tube 330 to lock thestiffener 330 against longitudinal movement with respect to the outertube 340.

The handle 321 of inner wire 320 can include a distal taper 327 toreleasably engage the inner wire 320, as shown in FIG. 21. In thismanner, the handle 321 can be removed from the wire 320 to enableremoval of the intermediate tube 330 and outer tube 340 from thesurgical site by sliding proximally over the wire 320, leaving wire 320in place. The proximal end of the handle 321 can include a lumen 328 toengage an extension wire (not shown) to increase the length of the innerwire 320.

Alternately, a torque type handle can be used to control the inner wireand can be positioned at a desired portion along the proximal exposedwire and can be configured so as to lock and unlock on the other wireswhile at the same time engaging the handle of the other wire. FIGS.22-24 illustrate an example of this showing another alternate embodimentof an engagement region with an interlocking feature. A collet 422 has adistal tapered region with a plurality of slots 423. A series ofexternal threads 424 threadingly engage internal threads 434 of collar432. Collar 432 is attached to a proximal end of the stiffener tube 430.

In use, collet 422, which encircles inner wire 420, is inserted withinthe opening 435 of handle or collar 434. In this position, collet 422 isattached to collar 434 but inner wire 420 can still freely movelongitudinally within intermediate stiffener tube 430 and outer tube440. If the user decides to fix (lock) the position of the inner wire420 to prevent longitudinal movement, handle surface 426, preferablytextured to enhance grasping, is gripped and rotated as shown in FIG.24. This advances the collet 422 further into the collar 432, resultingin the internal taper of the collar compressing the slotted region ofthe collet 422 to apply a clamping force on the inner wire 420. Thisclamping force applied by the collet 424 prevents longitudinal movementof the inner wire 420. To free the inner wire 420 for longitudinalmovement, the collet 424 is rotated in the opposite direction to retractthe collet 424 to allow it to expand to loosen the grip on the innerwire 420. Thus, the inner wire 420 and stiffener tube 430 can beselectively interlocked at a desired axial position of these members.That is, after movement of the members to the desired axial position,the user can rotate the collet the lock the members.

In the alternate embodiment of FIGS. 26-28, the proximal end 531 ofhandle 538 of intermediate stiffener tube 530 is dimensioned to receivecollapsible slotted member or collet 522 which encircles inner wire 520.More specifically, slotted member 522 has a tapered region 525,progressively decreasing in diameter toward a distal end, and anelongated slot or slots 524 formed therein and extending through theslotted member 522. That is, slot 524 can be formed so it extendsthrough the opposing wall to form an opposing slot, also labeled as slot524 in FIG. 28 and shown in phantom. The slots 524 are illustrativelyshown extending substantially longitudinally and equidistantly spaced,but could alternatively extend in other orientations and spacings, and adifferent number of slots can be provided to achieve the collapsibilityand clamping function. Slotted member 522 has a longitudinal opening 523extending along its length to receive the inner wire 520 therethrough.

In the normal non-collapsed position, the longitudinal opening 523 ofslotted member 522 has a dimension larger than the outer diameter of theinner wire 520 so the inner wire 520 can freely slide therethrough. Whenit is desired to lock the position of the inner wire 520 with respect tothe intermediate or stiffener tube 530, the slotted member 522 is slidover the inner wire 520 and inserted into the opening 527 at theproximal end 531 of handle 538 of intermediate tube 540. Due to theinternal diameter of the handle 538, when the slotted member 522 isinserted a sufficient distance, the wall of the handle 538 will apply aclamping force on the slotted member 522, thereby collapsing it aroundthe inner wire 520 to reduce the diameter of the longitudinal opening523 and provide a clamping force to prevent longitudinal movement of theinner wire 520. Thus, the user can selectively lock the members whendesired to fix their axial position. When it is desired to free theinner wire 520 for longitudinal movement, the slotted member 522 ismoved in the opposite direction, freeing itself from the confines of thehandle 538 to allow it to expand back to its normal position (return thelongitudinal opening to its larger diameter) to loosen the grip on theinner wire 520. In a preferred embodiment, the slotted member 522 ismade from a superelastic material such as Nitinol to ensure repeatedreturn to the previous configuration after repeated locking (clamping)and unlocking. Other materials are also contemplated. This Nitinol lock522 can be slid proximally over the inner wire 520 and removed to enableremoval of the outer tube 540 and intermediate tube 530 by sliding thesetubes proximally over the inner wire 520.

In a two component system (without a stiffener), the slotted member 522on the inner member would slide into a proximal portion of the outertube (similarly dimensioned to handle 538) for clamping and locking ofthe outer tube and inner member.

A threaded engagement as shown in FIG. 26 fixes the position of theintermediate stiffener tube 530 and the outer tube 540. Morespecifically, the proximal end 542 of outer tube 540 has a series ofmale threads 546. These threads engage the internal female threads 537on the distal end 536 of the handle 538 attached to or integral with thestiffener tube 530 to interlock the outer tube 540 and stiffener tube530.

In all other respects, the guidewire system of FIGS. 26-28 andcomponents and methods of use are the same as that described herein withrespect to the other embodiments. The engagement regions (mechanisms forinterlocking the members) of FIGS. 26-28 can be used with the variousembodiments of the members described herein, including for example theslotted stiffener and outer hypotubes.

In an alternate embodiment illustrated in FIG. 29A, the proximal end 741of outer tube 740 is crimped to form a reduced diameter portion and adistal end of intermediate tube 630 is flared out at region 738 to forma handle to be fitted over proximal end 741 to provide frictional(locking) engagement between the intermediate tube 630 and outer tube740. In one embodiment by way of example, the outer tube can have adiameter of about 0.035 inches and is crimped down to about 0.033 inchesand the intermediate tube has an attached tube portion with a flaredportion of about 0.035 inches in diameter welded to the proximal end ofthe intermediate tube. This is described in more detail below, forexample with the guidewire system having a fluid connector, but can beused with other systems.

FIG. 29-31 illustrate alternate embodiments of the guidewire systemwhich enables fluid flow through the distal tip. Referring initially toFIG. 29, the three component guidewire system 600 is similar to theaforedescribed embodiments as it includes an inner member 620, anintermediate member (stiffener) 630 and an outer member 740. Theintermediate member 630 and/or the outer member 640 are preferably inthe form of a hypotube with slots in the form as shown in FIG. 18 or18B, but other slot arrangements are also contemplated. The threemembers move with respect to each other in the manner described above tochange the stiffness and diameter of the guidewire and therefore forbrevity are not repeated herein. Further, the members can interlock inthe various ways described above, also for brevity not repeated herein.

The guidewire system 600 of FIG. 29 differs from the aforedescribedguidewire systems in the provision of fluid injection. Morespecifically, guidewire system 600 includes a connector 700, preferablya Touhy Borst type connector, having a proximal end portion 702 and adistal end portion 704. The proximal end portion 702 includes externalthreads 706 which mate with internal threads 708 of proximal knob 710.Rotation of proximal knob 710 in a first direction compresses theproximal end portion of the connector 700 which in turn compressesinternal collar 712 to apply a clamping force thereon. Internal collar712 also provides a seal and has an opening to receive inner member 620therethrough. Thus, rotation of proximal knob 710 in a first directionclamps the proximal end portion 702 of connector 700 to an intermediateportion of the inner member 620.

The distal end portion 704 of connector 700 includes external threads726 which mate with internal threads 728 of distal knob 721. Rotation ofdistal knob 721 in a first direction compresses the distal end portionof the connector 700 which in turn compresses internal collar 722 toapply a clamping force thereon. Internal collar or seal 722 has anopening to receive a proximal end of intermediate member 630therethrough. Thus, rotation of distal knob 721 in a first directionclamps the distal end portion 704 of connector 700 to the proximal endof the intermediate member 630. In this manner, the connector 700 isattached to a proximal end of the intermediate member 630.

The connector 700 includes a side arm 730 in fluid communication withthe internal channel 703 of the connector 700. This internal channel 703is in fluid communication with the proximal opening 632 in intermediatemember 630. Consequently, fluid injected through the side arm 730 flowsinto internal channel 703, through the proximal opening 632 inintermediate member 630 and through the gap 634 defined as the annularspace between the inner wall of the intermediate stiffener 630 and theouter wall of the inner member 620. The fluid flows through this gap orlumen, and out the distal end of the outer member 640.

In an alternate embodiment of the guidewire system illustrated in FIGS.30 and 31, a two component guidewire system is provided. The twocomponent guidewire system 800 includes an inner member 820 and an outermember 840, preferably in the form of a slotted hypotube similar tohypotube 740. In this simplified construction, relative movement of theinner member 820 and outer member 840 adjusts the diameter of theguidewire and adjusts the stiffness of the guidewire without the use ofan intermediate stiffener tube. That is, if a smaller and more flexibleguidewire is desired, the inner member, e.g. a 0.014 wire, can beadvanced/exposed relative to the outer member 840. If a stifferguidewire is desired, the outer member 840 is advanced over the innermember 820, while preferably maintaining the position of the innermember 820. This two component system can be utilized with the fluidinjection connector and capabilities of FIGS. 30 and 31 as well as withguidewire systems without such connectors. In the two component system,the inner member would lock to the outer member rather than thestiffener (intermediate tube). This can be achieved in the mannersdescribed above with respect to the engagement of the inner member andstiffener. For example, a collet or slotted member similar to slottedmember 522 of FIG. 28 on the inner member can be clamped by the handleportion of the outer member as it is selectively inserted therein. Theslotted member would be approximately sized for such engagement.

In the embodiment of FIGS. 30 and 31, the two component system 800 has aconnector 900 similar to connector 700 of FIG. 29. More specifically,connector 900, preferably a Touhy Borst type connector, has a proximalend portion 902 and a distal end portion 904. The proximal end portion902 includes external threads 906 which mate with internal threads 908of proximal knob 910. Rotation of proximal knob 910 in a first directioncompresses the proximal end of the connector 900 which in turncompresses internal collar 912 to apply a clamping force thereon.Internal collar 912 also provides a seal and has an opening to receiveinner member 820 therethrough. Thus, rotation of proximal knob 910 in afirst direction clamps the proximal end portion 902 of connector 900 tothe inner member 820.

The distal end portion 904 of connector 900 includes external threads926 which mate with internal threads 928 of distal knob 921. Rotation ofdistal knob 921 in a first direction compresses the distal end portion904 of the connector 900 which in turn compresses internal collar 922 toapply a clamping force thereon. Internal collar or seal 922 has anopening to receive outer member 840 therethrough. Thus, rotation ofdistal knob 921 in a first direction clamps the distal end portion 904of connector 900 to the outer member 840. In this manner, the connector900 is attached to a proximal end of the outer member 840.

The connector 900 includes a side arm 930 in fluid communication withthe internal channel 903 of the connector 900. This internal channel 903is in fluid communication with the proximal opening 842 in outer member840. Consequently, fluid injected through the side arm 930 flows intointernal channel 903, through the proximal opening 842 in outer member840 and through the gap 844 defined as the annular space between theouter wall of the inner member 820 and the internal wall of the outermember 840. The fluid flows through this gap or lumen space, exiting thedistal end of the outer member 840. This provides an increased gapdiameter compared to the three component system of FIG. 29 because ofthe absence of the smaller diameter stiffener tube.

Various types of fluids can be injected through the guidewire systems.One type of fluid that can be injected is a radiopaque contrast forangiographic visualization. Other types of fluids include but are notlimited to embolics and drugs. It is also contemplated that the innerwire can be removed to provide a larger lumen for injection of fluids ormaterials such as bioglues, microspheres, microbeads and/or emboliccoils. Note that with the inner wire removed, proximal knob 910 (or knob710) can be rotated to clamp further on collar 912 to provide a seal.

It should also be appreciated that in preferred embodiments, thecomponents (inner, intermediate and outer members) of the guidewiresystem of FIG. 26, as in the other preferred embodiments of theguidewire systems disclosed herein, do not exceed a diameter of about0.038 inches, and more preferably do not exceed a diameter of about0.035 inches.

In an alternate embodiment shown in FIG. 12, the inner wire handle 124′is removable from inner wire 120′ by unscrewing. More specifically,handle 124′ is attached to inner wire 120′ by a screw thread 121′ suchthat the handle 124′ can be unscrewed from inner wire 120. This allowsouter wire 140 and intermediate wire 130 to be removed by retraction(proximal movement) over the length of the inner wire 120′, therebyleaving only the softer, smaller diameter wire in place.

A conventional extension wire W can optionally be attached to the innerwire 20 (or other inner wires described herein) by a friction fit asshown in FIGS. 8 and 9. That is, a recessed, portion of female taper ofinner wire 20 receives a male tapered distal end W1 of extension wire W.

It is also contemplated that the outer and intermediate wires could beheld in place and the inner wire removed and replaced with another 0.014inches wire, such as a conventional 0.014 wire currently being used forsurgical procedures.

The aforedescribed guidewires of the present invention provide a methodof adjusting the stiffness and size of a guidewire without fullwithdrawal of the guidewire from a patient's vascular system. The usewill be described in conjunction with guidewire 10, however it should beappreciated that the description is applicable to the other threecomponents guidewire systems discussed herein.

In one method of use, the guidewire 10 is advanced into the vascularsystem from a remote site, such as the femoral artery F (see FIG. 3),with the outer wire 40 and stiffener 30 in the retracted position toexpose a substantial length of the inner wire 10 to expose a smallerwire diameter as shown in FIGS. 1 and 4. This provides for increasedflexibility of the guidewire system and less trauma to the vessel. Noteit is also contemplated that the guidewire is inserted from other sitessuch as the jugular vein or radial artery.

After initial advancement of the guidewire 10 through the vascularsystem en route to the target site such as the carotid artery C (FIG.3), if a tortuous vessel portion or other anatomy is encountered whereinthe inner wire 20 lacks the requisite pushability and stiffness, theouter wire 40 is slid in a distal direction over the inner wire 20,while maintaining the position of the inner wire 20, avoiding the needto remove the inner wire 20 from the patient. This creates a stifferguidewire to increase the pushability of the guidewire system 10 toenable it to advance through the curved vessel portion (see FIG. 5).

If during advancement, the outer wire 40 lacks the requisite pushabilityor stiffness to advance through a tortuous vessel portion or otheranatomy, the stiffener 30 can be advanced in a distal direction withinthe outer wire 40 and over the inner wire 20 to increase the overallstiffness of the guidewire 10, as shown in FIG. 1B.

After advancing through the tortuous vessel, the stiffener 30 can bewithdrawn if desired, leaving the more flexible outer wire 40 foradvancement.

If during advancement of the guidewire 10 with outer wire 40 coveringthe inner wire 20 a restricted passage in the portion of the vessel isencountered such that the vessel lumen dimension is less than the outerdiameter of the outer wire 40, the outer wire 40 can be retracted in aproximal direction to expose a substantial length of the inner wire 20.The smaller diameter inner wire 20 can then be used to advance throughthe restricted passage of the vessel lumen.

As can be appreciated, the wires can be slid relative to one another (asdefined herein) during the advancement of guidewire 10 to the treatmentsite any number of times as desired to provide the requisite diametersize, flexibility and stiffness.

Once the treatment site is reached, the stiffener 30 and outer wire 40can be slid proximally over the inner wire 20 and removed from thepatient, e.g. by removing the interlocking component of the innermember, thereby leaving the inner wire 20 in the patient to function asa rail for over the wire catheter and/or device insertion.Alternatively, the guidewire 10 can remain in place with the largerdiameter wire 40 functioning as a rail for over the wire catheter and/or device insertion. In certain embodiments, fluid can be injectedthrough the guidewire.

Although the method of use was described in relation to guidewire 10,the other guidewires disclosed herein would be advanced in a similarfashion. In the embodiment with a handle, the handle or torquer would beremoved if it was desired to remove the outer wire and stiffener.

Additionally, the method was described above with the guidewire systeminitially inserted so the inner wire extends from the outer wire. It isalso contemplated that if a larger wire is desired for initialinsertion, the guidewire system would be inserted with the inner wireretracted. Then the inner wire can be advanced to be exposed if asmaller size or increased pushability is desired.

The two component system works in a similar fashion except without astiffener tube, relying on the interaction of the inner member and outertube for diameter and stiffness/flexibility adjustment.

While the above description contains many specifics, those specificsshould not be construed as limitations on the scope of the disclosure,but merely as exemplifications of preferred embodiments thereof. Forexample, one or more of the wires can contain a hydrophilic coating.Those skilled in the art will envision many other possible variationsthat are within the scope and spirit of the disclosure as defined by theclaims appended hereto.

What is claimed is:
 1. A medical guidewire system comprising a firstinner member having a first outer diameter, a second intermediate memberhaving a second outer diameter larger than the first outer diameter, anda third outer member having a third diameter larger than the secondouter diameter, the second member having a longitudinally extendingopening to receive the first member for relative sliding movement withrespect to the first member, the third outer member having alongitudinally extending opening to receive the second member forrelative sliding movement with respect to the first and second member,the first member having a first stiffness, the third member having athird stiffness greater than the first stiffness, and the second memberbeing movable with respect to the third member to provide the thirdmember with a second stiffness greater than the third stiffness, whereinthe third member is configured as a rail for over-the-wire catheterinsertion.
 2. The guidewire system of claim 1, wherein the first membercomprises a wire having a solid core for at least a majority of itslength.
 3. The guidewire system of claim 1, wherein the third membercomprises a wound wire.
 4. The guidewire system of claim 1, wherein thethird member comprises a hypotube.
 5. The guidewire system of claim 1,wherein the second member is a hypotube.
 6. The guidewire system ofclaim 1, further comprising a first handle removably attached to aproximal portion of the first member to enable removal of the second andthird members from the guidewire system.
 7. The guidewire system ofclaim 6, further comprising a second handle attached to a proximal endof the second member, the second handle interlocking with the thirdmember to fix the position of the second and third members with respectto each other.
 8. The guidewire system of claim 7, wherein the secondhandle has a mating tapered region to frictionally interlock with thethird member.
 9. The guidewire system of claim 1, wherein the secondmember includes a second handle having a threaded member to clamp theinner member.
 10. The guidewire system of claim 1, further comprising astop limiting relative movement of the second and third members suchthat a distalmost end of the second member cannot extend to a distalmostend of the third member.
 11. The guidewire system of claim 1 wherein thethird member comprises a hypotube having a series of slots formed in asidewall to increase flexibility.
 12. The guidewire system of claim 11,wherein the second member comprises a hypotube with a series of slotsformed in a sidewall to increase flexibility.
 13. The guidewire systemof claim 11, wherein the space between the slots increases toward aproximal end of the hypotube.
 14. The guidewire system of claim 1,wherein the longitudinally extending opening of the third member has areduced diameter portion at a distal end portion.
 15. A multi-componentmedical guidewire system comprising first, second and third coaxiallypositioned members relatively slidable with respect to one another,wherein the second member is coaxially positioned between the first andthird members and has a sufficient stiffness to selectively increase thestiffness of the guidewire system upon positioning within a distalportion of the third member, and wherein the third member is configuredas a rail for over-the-wire catheter insertion.
 16. The guidewire systemof claim 15, wherein the second member interlocks with the third memberto fix the second and third members in position.
 17. The guidewiresystem of claim 15, wherein the first member interlocks with the secondmember to fix the axial position of the first member.
 18. The guidewiresystem of claim 15, wherein the first member has a diameter of about0.014 inches and the third member has a diameter of about 0.035 to about0.038 inches.
 19. A multi-component guidewire system comprising first,second and third coaxially positioned members relatively slidable withrespect to one another, each of the members having an engagement regionat a proximal end portion, wherein the engagement region has aninterlocking feature to interlock with another engagement region to fixthe relative position of the respective members.
 20. The guidewiresystem of claim 19, wherein the engagement region of the first membercomprises a first handle removably mounted to the first member.
 21. Theguidewire system of claim 19, wherein the engagement region of the firstmember includes a first handle and the engagement region of the secondmember includes a second handle, the interlocking feature including atapered region on the first handle engaging a mating region of thesecond handle.